knocked out before checkup stage / poison interaction error?

addison1134

If a pokemon receives enough damage to get knocked out from an attack, but that attack poison's them. shouldn't they be knocked out before poison damage applies?

Where I found this bug specifically- Toxicroak ex' attack killed 2 different mons and then the poison damage applied tho wasn't needed for the knock out.

I had Kingdra with deep sea king ability on my bench which reads "when your active pokemon is knocked out by damage from an attack..." The effect of my Kingdra wouldn't activate because the poison damage would show before the pokemon would get knocked out despite damage being enough to kill.

Is this a bug or does poison apply after damage even if it's enough to knock out?